It looks like a Visitor mothership that's had extra bits stuck on to it, like those ridgelines and what looks like a bridge module.I once emailed Michael Okuda about this object many years ago. He seemed to think it was something left over from the V TV series. It does vaguely resemble a Visitor mothership, but there are other details that don't quite match up.
It's kind of in a gray area for me. It doesn't really fit into what you'd traditionally call a saucer ship to me, but you could argue it's close enough.